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Re: [boost] JSON Parser GSoC 2013
by John Venarchick 12 Apr '13

12 Apr '13

> 2013/4/12 Michael Marcin <mike.marcin(a)gmail.com> > >> Arindam Mukherjee wrote: >> >>> In JSON we typically deal with maps and arrays. The arrays themselves >>> could >>> have arbitrary types (string, object, array, numeric, boolean, null) as >>> elements. The key types in the maps are always strings and the value types >>> in the maps could be anything that can appear in an array, including >>> another map or array. >>> >>> Due to this, I'd imagine being able to use Boost.Variant or Boost.Any in a >>> list and as a value_type in a map would help. >>> >>> I have been doing some work with JSON and boost by modifying the current 1.53 ptree. I created a type for use as the data_type of the ptree that represents the various options for JSON data (no value, null value, bool, integer, float, string). It uses boost::variant and visitors. I have it working for my purposes, but would want to make it a little nicer before submitting a patch. I also implemented property_tree::translator_ between to make it work with the spirit classic parser in json_parser_read and json_parser_write. I can post more if anyone is interested. I'm also working a generic way to load arbitrary structures from the created ptree. -John V

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Re: [boost] [gsoc-2013] Physics Library Abstraction Layer
by Preston Hamlin 12 Apr '13

12 Apr '13

Considering that I have received positive feedback on this project, I shall likely make a proposal for it when the time comes. Before then, I would like to pin down the scope and breadth of this library. I am in possession of the PhysX SDK and have been reading it over to come up with some questions to ask so that (should my proposal be accepted) I would not have to be overly concerned later. On the first page of the SDK documentation, it is denoted that several distributable (PhysX) DLLs are required for applications on the Windows platform. Since Boost is a library project, I am unsure what to do with DLL files other than unceremoniously stick them in a Resources folder until the time comes, or have a script built into one of the library files. Perhaps contact Nvidia? I have worked a little with WinAPI, but not in the case of using an SDK. Since this would be a beginning point for the library, might I assume that complex mesh deformations and simulations (e.g. fluid dynamics) are beyond the scope of what should be done over the summer? Certainly one could implement certain models with effort, but I mean that the library will lack explicit methods for something of the following degree: http://www.youtube.com/watch?v=7Who8EpbvCY The same question goes for Multithreading. I will continue to tinker with and read over the SDK(s) and brush up on my matrix arithmetic. For the proposal, should I have a couple concrete classes? Or would pseudocode/feature descriptors suffice? More questions on the way, -Preston

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Fwd: How to start contributing for Boost
by Hasit Bhatt 12 Apr '13

12 Apr '13

I'm 3rd year B.Tech student in Computer Science with quite good proficiency in c,c++ and python. I'm applying for Google Summer Of Code. How should I start?

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Can C++11 INVOKE be defined with C++98 compilers?
by Vicente J. Botet Escriba 12 Apr '13

12 Apr '13

Hi, I would like to implement C++11 INVOKE on C++98 compilers. I have a C++11 implementation on boost/thread/detail/invoke.hpp based on the one of libc++. Could this be done or there is something that can not be done inherently? Best, Vicente

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GSoC 2013: ODE or B-trees?
by Артём Серов 11 Apr '13

11 Apr '13

Hello! My name is Artem Serov. I would like to participate GSoC in Boost and I have a dilemma. I don't have enough information to choose one of two projects in boost: B-trees and Ordinary Differential Equations and want to find out which project matches me better. Before composing a formal application (with all formal requirements) for a project and deeper investigating of the environment i hope to get a piece of advice about my doubts. A few facts: - the 3rd year student of Moscow Institute of Physics and Technology (State University), Russia. - ~1 year exprerience of C/C++ industrial programming in Intel as intern. - no experience in open souce project contribution. Both projects are very challenging and interesting for me. ODE: I had cources of Theory of ODE, Computional Mathematics and Parallel programming (OpenMPI) at the university, so i am familiar with the topic. B-trees: The topic "B-trees" is located in the additional list of ideas for GSoC, so there is no concrete information except the title. Could someone (maybe who have put this in the ideas list) will tell anything: maybe requirements, any thoughts, why is it mentioned in GSoC ideas list, why isn't this idea in a main list or any information like in projects in the main ideas list, please? What would you advise me: to apply for the concrete project from the main list or to develop the project from additional list? What is preferable for the community? Could you give a kind of very brief estimation and comparisson of difficulty of both projects? -- Thanks, Artem Serov

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[Graph] Efficiently finding cycles in a (multi)graph
by Louis Dionne 11 Apr '13

11 Apr '13

Dear Boost, I have implemented the `hawick_circuits` algorithm described in [1] for finding all the elementary circuits of a directed (multi)graph. I implemented it in a generic fashion, planning to propose it for inclusion in Boost. Boost.Graph currently contains the `tiernan_all_cycles` algorithm for finding all the cycles in a graph. However, it is undocumented and it has a time bound (for which no precise analysis is provided) that makes it unsuitable even for moderately sized graphs. In fact, I implemented `hawick_circuits` because `tiernan_all_cycles` did not cut it for my application. My implementation is available at [2]. It is licensed under the Boost license and was tested using the test suite at [3]. I am posting this message for two reasons: 1. To know whether there is interest for such an algorithm in Boost.Graph. 2. To spread the word that this implementation exists for C++, to save people the hassle of reinventing the wheel before Boost.Graph officially provides it. I will create a Trac ticket if there is interest, but note that I won't submit a patch immediately because I am in deep juice with school right now. Regards, Louis Dionne P.S.: More information on the test suite can be found at [4]. [1] http://bit.ly/12LMwIr [2] http://bit.ly/10MSAhW [3] http://bit.ly/YdLHVn [4] http://bit.ly/16SvlW6

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GSoC 2013
by İslam Yaşar 11 Apr '13

11 Apr '13

Hi, I'm a graduate student and work since 2 years as a C++ developer on Unix-like systems (FreeBSD and Linux), i want to implement a library for Boost. It is a thread-safe queue that is implemented on disk. You can use it as a IPC. Is anyone interested to mentor this project ? Thanks Islam Yasar

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Boost.uBLAS for GSoC 2013
by Sathyam Vellal 11 Apr '13

11 Apr '13

Hello. I'm Sathyam Vellal, a 3rd year undergraduate student pursuing Computer Science. I'm interested in contributing to Boost.uBLAS in unifying the vector and matrix representations. I've looked at the docs ( http://www.boost.org/doc/libs/1_53_0/libs/numeric/ublas/doc/index.htm) to get an idea of the library. Does anyone have any suggestions on how I could proceed more and connected to this project? Thank you -- Sathyam M Vellal Computer Science and Engineering, P.E.S. Institute of Technology, Bangalore, India.

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GSoC 2013 : Boost.uBLAS
by Jignesh Jain 11 Apr '13

11 Apr '13

I am interested in this project for Gsoc, which involves unification of vector and matrix libraries. I have been browsing boost ublas code, but have no idea about how should I begin as I am totally new to Boost. Can Someone please guide me some approach for getting started in this project. Thank you.

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Boost.Multiprecision GSoC 2013
by Nikhar Agrawal 10 Apr '13

10 Apr '13

Hi, My name is Nikhar Agrawal. I'm a 2nd year Computer Science student. I'm interested to work for Boost in GSoC and I found the project Boost.Multiprecision really really interesting. Any pointers on how should I go about it? Meanwhile, I'll go through this book:- http://www.loria.fr/~zimmerma/mca/mca-cup-0.5.1.pdf Thanks

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[thread] using Boost.Thread with move-only arguments
by Fernando Pelliccioni 10 Apr '13

10 Apr '13

Hi Vicente, I have an issue with Boost.Thread contructor using move-only type arguments. The "Thread Constructor with arguments" section of the documentation says ... template <class F,class A1,class A2,...> thread(F f,A1 a1,A2 a2,...); Preconditions: F and each An must by copyable or movable. http://www.boost.org/doc/libs/1_53_0/doc/html/thread/thread_management.html… "An" could be copyable or movable, but the following example fails to compile... error: use of deleted function 'A::A(const A&)' //Begin code ------------------------------------ #include <boost/thread.hpp> struct A { A() = default; A( const A& other) = delete; A& operator=( const A& other) = delete; A( A&& other) = default; A& operator=( A&& other) = default; void run() {} }; void f( A a ) { a.run(); } void exec_boost() { A a; boost::thread t( f, std::move(a) ); t.join(); } //End code -------------------------------------- I think we should modify ... template <class F,class A1> thread(F f,A1 a1,typename disable_if<boost::thread_detail::is_convertible<F&,thread_attributes >, dummy* >::type=0): thread_info(make_thread_info(boost::bind(boost::type<void>(),f,a1))) { start_thread(); } ... by ... template <class F,class A1> thread(F&& f,A1&& a1,typename disable_if<boost::thread_detail::is_convertible<F&,thread_attributes >, dummy* >::type=0): thread_info(make_thread_info(boost::bind(boost::type<void>(),f,boost::forward<A1>(a1)))) { start_thread(); } ( In the all family of related ctors in "boost/thread/detail/thread.hpp" ) But, I don't know if boost::bind is forwarding its arguments I think we should modify Boost.Bind to be similar to std::bind. Is there any reason why Bind has not changed so far? Have you found any limitations? If Bind can not be changed, I think Boost.Thread should use some other tool similar to Bind to make forwarding parameters. GCC Libstdc++ use a Bind-lite tool for std::thread. I can work on this if you want. What do you think? Environment: Windows 7 64bits MinGW - GCC 4.7.2 MSVC 2010 MSVC 2012 Boost 1.53.0 Non-Variadic template code branch Regards, Fernando Pelliccioni

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Re: [boost] GSoC 2013 : Implementing Dynamic Programming Algorithms
by Aman Gupta 09 Apr '13

09 Apr '13

Hi, Thanks for the reply. The first thing I want to implement is a Integer-Knapsack problem which takes in a precision error(i.e. an epsilon which is a indicator of the allowed error in the input) The input parameters are Weights, Values and the error. The first thing to do is massage the values according to the error (e.g. if the value is ~10^4 divide it down to ~10^3 according to the error) then run the a dynamic programming algorithm, which has a running time of O(n^3/e) (n : number of items, e :error) Hence, an arbitrarily close approximation is possible with a running time trade-off. Also, a vanilla variety of the knapsack problems(with small instances) which gives the optimal solution can also be implemented. I also want to implement the assignment problem, which also arises in a lot of situations in real life ( http://en.wikipedia.org/wiki/Assignment_problem) using the Hungarian Algorithm. I realize this requires effort but I'm really interested in adding a feature to the boost library. Regards, Aman Gupta

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GSoC 2013 - Boost registration?
by Paul A. Bristow 09 Apr '13

09 Apr '13

http://www.google-melange.com/gsoc/events/google/gsoc2013 March 18: 19:00 UTC Mentoring organizations can begin submitting applications to Google. March 29: 19:00 UTC Mentoring organization application deadline. Just checking that Boost has/is registering? Paul --- Paul A. Bristow, Prizet Farmhouse, Kendal LA8 8AB UK +44 1539 561830 07714330204 pbristow(a)hetp.u-net.com

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GSoC 2013 : Implementing Dynamic Programming Algorithms
by Aman Gupta 09 Apr '13

09 Apr '13

Hi, I am Aman Gupta from BITS-Pilani India, I am a 4th year Undergraduate Student majoring in Computer Science. I've noticed that boost does not contain dynamic programming algorithms like Integer-Knapsack, Longest Common Sub-sequence. I was thinking that implementing this would be a good project. I realize most of these problems are non-polynomial in complexity but I was thinking implementing them to a certain size will not be problem. Also, since some of the dynamic programming algorithms have alternate greedy algorithms which compromise on correctness but are faster, implementing those can be useful. The knapsack problem(which comes in a lot of situations) for which there exists an algorithm which gives an arbitrarily close approximation to the optimal value can be implemented. ( e.g. f(weights,values,error) could be the function, the user has a trade-off between error and computation time). I think it could be useful in situations where the user just decides the error he wants or perhaps how fast he wants his computation. Please let me know if this seems like a valid project idea to you! Thanks, Aman Gupta

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[move] move's is_convertible does not compile with aligned data
by Tobias Loew 09 Apr '13

09 Apr '13

The implementation of move's is_convertible-type has the same problems on MSVC with aligned types as reported for type_trait's is_convertibale in Ticket #5271 https://svn.boost.org/trac/boost/ticket/5271 As type_trait's implementation has been fixed, a simple solution would be letting the user (and not the code in move.hpp:41) [not] define BOOST_MOVE_AVOID_BOOST_DEPENDENCIES regards Tobias -- View this message in context: http://boost.2283326.n4.nabble.com/move-move-s-is-convertible-does-not-comp… Sent from the Boost - Dev mailing list archive at Nabble.com.

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boost/thread.hpp UBICOM processor
by Aswin Paranji 09 Apr '13

09 Apr '13

Hi, I'm trying to compile boost library 1.53 using the ubicom toolchain provided by our embedded partner. During compilation of the boost library there was a linker error (_sync_fetch_add). This was overcome by adding define statement BOOST_SP_USE_PTHREADS, along with FENCED in user-config.hpp. The application was linked properly. Running the application within the embedded box exits with a segmentation fault happening before printing the first line of the main function. This was narrowed down to boost/thread.hpp header. Removing the header allows the application to print the first line and return. The problem I have is, I do not have GDB/GDBServer to assist me. Also, i could not use back_trace as the toolchain does not have the necessary header files. Can anyone tell me what might be causing the problem. I'm sure there is some sort of conflict between the processor architecture with thread or the toolchain which was used to compile boost. The GCC version is 4.4.1 Appreciate if someone can help me on this. Thanks, Aswin Paranji

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[phoenix] doesn't compile with gcc 4.9 snapshot
by Nathan Ridge 08 Apr '13

08 Apr '13

Hi, I'm trying to compile some code that uses Boost with a GCC 4.9 snapshot, but something seems to be going badly wrong. Something as simple as a file containing the include: #include <boost/phoenix/core.hpp> fails to compile, with the following errors: In file included from boost/proto/matches.hpp:42:0, from boost/phoenix/core/domain.hpp:12, from boost/phoenix/core/actor.hpp:17, from boost/phoenix/core.hpp:15, from test.cpp:1: boost/proto/traits.hpp: In instantiation of 'struct boost::proto::tag_of<boost::proto::_>': boost/phoenix/core/domain.hpp:25:18: required from here boost/proto/traits.hpp:241:42: error: no type named 'proto_tag' in 'struct boost::proto::_' typedef typename Expr::proto_tag type; ^ In file included from boost/phoenix/core/argument.hpp:15:0, from boost/phoenix/core.hpp:17, from test.cpp:1: boost/phoenix/core/terminal.hpp: In instantiation of 'struct boost::phoenix::detail::placeholder_idx<boost::proto::make<boost::is_placeholder<boost::proto::_value>()> >': boost/phoenix/core/terminal.hpp:122:18: required from here boost/phoenix/core/terminal.hpp:115:16: error: 'value' is not a member of 'boost::proto::make<boost::is_placeholder<boost::proto::_value>()>' struct placeholder_idx ^ The exact same code compiles fine with GCC 4.8 and earlier. Any ideas as to what might be going wrong? Thanks, Nate

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Boost.Graph for GSoC
by Daniel Mitchell 08 Apr '13

08 Apr '13

Hi all, I'm a researcher and graduate student at the University of Texas at Austin and I'm interested in doing a Boost.Graph project for GSoC. I was thinking of doing one or more planar graph algorithms, in particular the multiple source shortest paths algorithm for planar graphs described at http://courses.csail.mit.edu/6.889/fall11/lectures/L11.html The algorithm assumes that the sources are located on a single face. It proceeds by calculating the shortest paths tree from one source and then minimally modifying the tree to efficiently get the shortest paths from the other sources. The algorithm uses a dynamic tree data structure, so developing that data structure would be part of the project too. I've made prior contributions to BGL. I worked with Doug Gregor to implement color maps for the breadth first and Dijkstra's algorithms. One of my current areas of research is movement ecology, where planar graphs can be used to study movement. Let me know what you think. Daniel Mitchell

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[container] stable_vector::back() is broken in Boost 1.53
by Klaim - Joël Lamotte 08 Apr '13

08 Apr '13

Tested on both VS2010 and VS2012, boost 1.53, with default boost no option set: ############ #include <boost/container/stable_vector.hpp> #include <iostream> int main() { boost::container::stable_vector< int > values; values.emplace_back( 42 ); int& bad_value = values.back(); // bad address int& good_value = values.front(); int& also_good_value = values.at(0); // imply values[0] std::cout<< " ADDRESS OF BAD VALUE : " << &bad_value << std::endl; std::cout<< " ADDRESS OF GOOD VALUE : " << &good_value << std::endl; std::cout<< " ADDRESS OF ALSO GOOD VALUE : " << &also_good_value << std::endl; } ############ This code displays addresses of the bad_value object very low on Debug and very high on Release. I believe that .back() is broken. However, when I test there : http://liveworkspace.org/code/3F11CK$2 it seems to work with any available compiler. So either it's LiveWorkspace which use an older boost version, or this issue arise only on VC. I made a ticket: https://svn.boost.org/trac/boost/ticket/8412 Joel Lamotte

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GSoC 2013: Boost is a mentoring organization
by Boris Schaeling 08 Apr '13

08 Apr '13

Boost is a mentoring organization in this year's GSoC program. Thanks to everyone who added proposals to <https://svn.boost.org/trac/boost/wiki/SoC2013> and to Google for inviting us! According to the GSoC calendar at <https://google-melange.appspot.com/gsoc/events/google/gsoc2013> we have now two weeks where would-be student participants discuss application ideas. If you are interested in participating in the program - either as a student or as a mentor - get active now! :) 1) Have a look at our ideas list at <https://svn.boost.org/trac/boost/wiki/SoC2013>. Find something which interests you or think of a brand new project. 2) Send a mail to the mailing list at <mailto:boost@lists.boost.org> to let people know what you are interested in and what you have to offer. 3) Discuss your idea with others and try to turn it into an actual GSoC project. You need at least a project description, a goal, a mentor and a student. :) Boris

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Adding some image libs to boost build
by Christian Henning 08 Apr '13

08 Apr '13

I have added jpeg, png, and tiff jam files to boost trunk. These files will be needed by gil::io tests. There are still some remaining issues which I like to discuss in this thread: 1. building these libs sometimes requires renaming header and/or source files to the correct architecture. Should we leave that up to the user or should bjam take care of it. And if so, how will we configure that. One example is jpeg: see jconfig.vc -> jconfig.h 2. Tiff has a file nmake.opt which is included in the makefile. How will we include all those options? Regards, Christian

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Release milestone.
by Vicente J. Botet Escriba 08 Apr '13

08 Apr '13

Hi, I would like to merge some fixes in Boost.Thread, but I suspect that the release branche should be blocked as for https://svn.boost.org/trac/boost/wiki/ReleaseSchedule. On which stage (milestone) is the release process? Best, Vicente

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[gil] numeric extension, arithmetic operators
by Harg Tholan 08 Apr '13

08 Apr '13

Hey, Do we plan to overload arithmetic operators for Pixel as wrappers of the numeric extension? or should users derive a class from Pixel adding such functionality? ATM, for diving two pixels (rgb_8 for example), I have to call the division this way: pix_r = pixel_divide_t<rgb_8_pixel_t, rgb_8_pixel_t, rgb_8_pixel_t>().operator()(pix2, pix1); The thing is that I have a template class that makes use of operator/ at some point on one of the template parameters, and I would like to be able to use it with 'Pixel' type. Thank you!

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future<>::then() Error returning future<void> (on trunk)
by Fernando Pelliccioni 07 Apr '13

07 Apr '13

Hi Vicente, hi all, I noticed that in the trunk there is a implementation of future<>::then(). Thank you very much for your efforts to implement it! The following example, compiles OK boost::future<int> f1 = boost::async([]() { return 123; }); f1.then([](boost::future<int> const& f) { return std::string(""); }); But this one fails to compile: boost::future<int> f1 = boost::async([]() { return 123; }); f1.then([](boost::future<int> const& f) { }); Here future<>::then() have to returns future<void> like ... boost::async([]() { }); Am I right? On the other hand, have you taken into account the following paper? http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3451.pdf Regards, Fernando Pelliccioni.

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C++11 and compilers not supported by vendors any more
by Antony Polukhin 06 Apr '13

06 Apr '13

Hi, I've got an almost ready patch for Boost.Any, that adds rvalues support to it via Boost.Move. But the trouble is following: Current version of patch may (and would) break compilation on ancient compilers, like MSVC6, BCC 5.5 and g++ 2.95. It can be tuned, to work even on those platforms, but: * I have no access to those antiquities, so it is impossible to run tests * It will take huge amount of time, to make it work What is the current policy in such situations (may ancient compilers support be dropped)? -- Best regards, Antony Polukhin

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